What is the association between laboratory markers (platelet count, transaminases (liver enzymes), albumin, C-Reactive Protein (CRP)) and Acute Kidney Injury (AKI) severity in patients with Tropical Acute Febrile Illness?

Association of Laboratory Markers with AKI Severity in Tropical Acute Febrile Illness

Laboratory markers including low platelet count, elevated transaminases, hypoalbuminemia, and increased CRP are strongly associated with increased severity of acute kidney injury in tropical acute febrile illness, with the combination of these markers providing better prognostic information than individual parameters alone. 1

Key Laboratory Markers and Their Association with AKI Severity

Platelet Count

• Low platelet count serves as both a diagnostic and prognostic marker in TAFI-associated AKI, with lower counts associated with higher mortality and increased need for renal replacement therapy (RRT) 1
• Thrombocytopenia is present in approximately 70% of patients with dengue fever, a common cause of TAFI, and is significantly associated with AKI development 2

Liver Function Tests

• Severe transaminitis (elevated liver enzymes) is significantly associated with AKI in TAFI patients 3
• Higher serum glutamic pyruvic transaminase (SGPT) levels (450 vs 144, p=0.001) and alkaline phosphatase (ALP) levels (207 vs 42, p=0.001) are observed in TAFI patients who develop AKI compared to those who don't 2
• Hyperbilirubinemia is an independent risk factor for TAFI-associated AKI with an adjusted odds ratio of 2.4 (95% CI 1.1-4.9) 3

Albumin

• Hypoalbuminemia is significantly associated with AKI in TAFI patients 3
• Lower albumin levels are observed in TAFI patients with AKI compared to those without (2.65 vs 3.09, p<0.001) 2
• In the context of acute illness, albumin primarily reflects the inflammatory state rather than nutritional status 1

C-Reactive Protein (CRP)

• Elevated CRP levels are associated with increased mortality in AKI patients 4
• The ratio of CRP to prealbumin is independently associated with mortality in AKI patients after adjustment for age, gender, sepsis, and sequential organ failure assessment (SOFA) score 4

Integrated Assessment and Prognostic Value

• The Acute Dialysis Quality Initiative (ADQI) consensus recommends combining clinical assessment with biomarkers to optimize patient triage and intervention timing 1
• A combination of damage and functional biomarkers, along with clinical information, improves diagnostic accuracy of AKI and helps assess severity better than any single marker 1
• The CRP/prealbumin ratio shows increasing hazard ratios of 1.00 (reference), 1.85,2.25, and 3.89 across quartiles (p=0.01 for trend), demonstrating its value as a prognostic tool 4

AKI Incidence and Etiology in TAFI

• The incidence of AKI in TAFI varies widely in studies, ranging from 6.8% to 54% of patients 5, 3
• Leptospirosis appears to be the most nephrotoxic cause of TAFI, with almost all patients developing AKI and the highest rates of severe AKI (stages 2 and 3) and RRT requirement 5
• Dengue fever is commonly associated with milder forms of AKI (stage 1) 5
• Malaria (particularly falciparum) is another significant cause of AKI in TAFI 5, 6

Risk Factors and Clinical Implications

• Male gender (AOR 3.1), respiratory failure (AOR 4.6), hyperbilirubinemia (AOR 2.4), and obesity (AOR 2.9) are independent risk factors for developing AKI in TAFI 3
• The presence of AKI significantly increases mortality risk, with odds ratios of 6.9,20.2, and 25.6 for RIFLE Risk, Injury, and Failure categories respectively 6
• RRT requirement increases with AKI severity, with odds ratios of 3.4,28.8, and 178.8 for RIFLE Risk, Injury, and Failure categories respectively 6
• Multiple organ dysfunction syndrome (MODS), sepsis, and hypotension are significantly associated with AKI development and worse outcomes 2

Clinical Approach to Laboratory Monitoring

• Serial monitoring of platelet count, transaminases, albumin, and CRP is more valuable than single measurements for assessing AKI progression and prognosis 1
• Early detection of laboratory abnormalities can help identify patients at risk for developing severe AKI who may benefit from more aggressive management 3
• Patients with TAFI who present with high-grade fever, dyspnea, leukocytosis, severe transaminitis, hypoalbuminemia, metabolic acidosis, and proteinuria should be closely monitored for AKI development 3
• The RIFLE or KDIGO classification systems are valid and applicable in TAFI-related AKI for staging severity and predicting outcomes 5, 6